Well, BT seems to work under the assumption that humans can live long term on planets with significantly Greater than 1G Gravity considering that we have multiple canon planets with >1G surface gravity and two planets in Clan Space with 2G surface Gravity and I have a feeling that it isn't just Elementals living on them.
Point being that I think in this instance, they've either handwaved long term gravitational effects on human populations or they're working off the findings of that long term study and assuming that 2Gs are the maximum long term gravitational range of the human body.
Either way, in BT a human crew is probably fine with their ship kicking up to 2Gs to get out of dodge or get going somewhere fast with the in universe assumptions.
Battletech, like most Space Operas, is about 5% more science than Star Wars, and 10% more than Lord of The Rings. Most of the 'space' portion was informed not by science, or even known science, it's informed by watching Anime and B-roll movies, with occasional nods to novelizations of properties like Star Wars.
Basically less science than Niven's "Known Space" setting-which was published in the 1950s and 1960s or Pournelle's "Falkenberg's Legion" stories-which were, at least, contemporary to Battletech's era of creation, but not the type of sci-fi most of the people involved in designing the setting in the 1980s were even familiar with.
Mike Stackpole didn't KNOW that a fusion reaction from a reactor isn't like the fusion byproduct of a hydrogen bomb when he wrote that scene on (was it Twycross or Trell One?)-the exploding reactor scene. (hint: a mini-tokamak wouldn't do that, something most famously pointed out by now-staff-member/contributor Cray, who is an actual Materials Physicist.)
but, it's canon, so it happened.
If you're going to be drawing from 'The Expanse' for inspiration, that's about 55% more Science than Battletech can likely handle and still keep most of the base assumptions going.
I pointed out the gravity limits for one reason: "Why would you enter a system at the Zenith or Nadir jump points?" The answer, is because if you're hauling ground troops (and face it mate, most of the Naval in the setting is just an expensive bus for ground troops) then you have to accept that your crew might be trained to handle High-gees and hard vacuum,
but your passengers aren't.and even if they are, as someone who's been on a troop transport aircraft for sustained hours? they ain't gonna stay sitting in the acceleration couches. Loose objects becoming projectiles, including your passengers (the sole reason most dropships are in the air, along with many warships) is inevitable under hard thrust and gees.
This, will result in delivering stretcher cases instead of combat soldiers if you don't 'fly real careful and gentle with 'em'.
Basically Zenith and Nadir are the biggest, closest, stable points to the objective, ergo least amount of time spent at one gee, and least exposure for accidents to happen.
This is also going to inform all your naval design strategy-because?
Because Warships are there to get Ground Troops to the surface intact, along with their gear. That's the attitude IN the fiction-Navies are basically bus drivers, by the prevailing doctrine-and that doctrine prevails in every Great House, along with the Star League and the Clans.
it just happens that the existing designs, with their shirtsleeves environments, HarJel(for the Clans) and so on? fit that doctrine pretty solidly-the reason you don't have outer decks depressurizing, is that your ship is there to carry ground troops who don't come with their own pressure suits.
Your Commanding Officer on the ship? may have almost NO experience at space operations or deep space survival-because he's a 'mechwarrior, or an aerofighter pilot whose main experience is dogfighting in atmosphere, or a dropship jockey whose entire career has been landing and takeoff cycles onto planets.
Getting into more developed strategies and tactics navally, would require a source of personnel whose career focus isn't getting ground troops to the ground, then supporting them while there.
Tech-wise an 'expanse' style naval force is doable, it just doesn't fit the setting...at all. (well, outside of fanfictions, anyway. I love doing that in fanfic, but I'm under zero illusions that the kind of thinking I use would ever be in favor or adopted by anyone who Catalyst would offer a contract to.)
So, anyway, now that I've been a disruptive schmuck, let's get together and work out your DREAM naval rules, for games that Catalyst will never write, nor accept, nor likely play.
because it's fun, and I can be wrong.